Class: Musa::Scales::PentatonicMinorScaleKind

Inherits:
ScaleKind show all
Defined in:
lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_minor_scale_kind.rb

Overview

Minor pentatonic scale kind.

PentatonicMinorScaleKind defines the minor pentatonic scale, a five-note scale derived from the natural minor scale by omitting the 2nd and 6th degrees. It's the foundation of blues and rock improvisation.

Pitch Structure

5 diatonic degrees plus extended (6th-10th):

Scale Degrees (Roman numerals, lowercase for minor):

  • i (tonic): Root (0 semitones)
  • iii (mediant): Minor third (3 semitones)
  • iv (subdominant): Perfect fourth (5 semitones)
  • v (dominant): Perfect fifth (7 semitones)
  • vii (subtonic): Minor seventh (10 semitones)

Relationship to Natural Minor

Minor pentatonic = Natural minor minus 2nd and 6th degrees. This removes all semitone intervals, creating a scale with no dissonance.

Relative Major Pentatonic

A minor pentatonic shares the same notes as C major pentatonic. They are relative scales.

Musical Character

The minor pentatonic:

  • Has a bluesy, soulful quality
  • Foundation of blues and rock guitar solos
  • Works over both minor and dominant 7th chords
  • Easy to improvise with (no "wrong" notes)

Usage

a_pent = Scales[:et12][440.0][:pentatonic_minor][69]
a_pent.tonic     # A (69)
a_pent.dominant  # E (76)

See Also:

Constant Summary collapse

@@pitches = 
[{ functions: %i[i _1 tonic first],
pitch: 0 },
             { functions: %i[iii _2 mediant second],
pitch: 3 },
             { functions: %i[iv _3 subdominant third],
pitch: 5 },
             { functions: %i[v _4 dominant fourth],
pitch: 7 },
             { functions: %i[vii _5 subtonic fifth],
pitch: 10 },
             { functions: %i[viii _6 sixth],
pitch: 12 },
             { functions: %i[x _7 seventh],
pitch: 12 + 3 },
             { functions: %i[xi _8 eighth],
pitch: 12 + 5 },
             { functions: %i[xii _9 ninth],
pitch: 12 + 7 },
             { functions: %i[xiv _10 tenth],
pitch: 12 + 10 }].freeze

Class Method Summary collapse

Constructor Details

This class inherits a constructor from Musa::Scales::ScaleKind

Class Method Details

.grades ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_minor_scale_kind.rb', line 87

def grades
  5
end

.id ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_minor_scale_kind.rb', line 91

def id
  :pentatonic_minor
end

.pitches ⇒ Object 



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# File 'lib/musa-dsl/music/scale_kinds/pentatonic/pentatonic_minor_scale_kind.rb', line 83

def pitches
  @@pitches
end